#include <bits/stdc++.h>

using namespace std;

typedef long long int ll;
typedef double ld;

typedef pair<ll, ll> ii;
typedef vector<ll> vi;
typedef vector<ii> vii;

#define PB push_back
#define FOR(prom, a, b) for ( ll prom = (a); prom < (ll)(b); ++prom )
#define F(a) FOR(i,0,a)
#define FF(a) FOR(j,0,a)

#define EPS (1e-10)

#define INF (1ll<<61)

int main () {
	ios::sync_with_stdio(false);
	ll N,K;
	while(cin>>N>>K){
		vector<vi> a(N);
		vi c(K,0);
		F(N){
			ll w;cin>>w;
			FF(w){
				ll q;cin>>q;q--;
				a[i].PB(q);
			}
		}
		ll from=0, to=0, total=0, res=INF, cnt=0;
		while(from!=N){
			while(to!=from+N && total!=K){
				for(ll n:a[to%N]){
					if(c[n]==0)total++;
					c[n]++;
					cnt++;
				}
				//cout<<from<<' '<<to<<endl;
				to++;
			}
			if(total==K)res=min(res,cnt);
			for(ll n:a[from]){
				if(c[n]==1)total--;
				c[n]--;
				cnt--;
			}
			//cout<<from<<' '<<to<<endl;
			from++;
		}
		cout<<(res==INF?-1:res)<<endl;
	}
	
	return 0;
}